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Four new complexes, [Cu 9 L 6 ( µ 3 -ClO 4 ) 2 ](ClO 4 ) 4 ·4CHCl 3 1 , [Cu 3 L 2 (H 2 O) 2 ](ClO 4 ) 2 ·3H 2 O 2 , [Cu 6 L 4 (N 3 ) 2 ](ClO 4 ) 2 3 and [Cu 2 L(CH 3 COO) 2 ] 4 , where H 2 L stands for the Schiff base N , N ′-bis[(2-hydroxybenzilideneamino)-propyl]-piperazine, were obtained and structurally characterized. Compounds 1 , 2 and 3 contain the Cu 3 L 2 2+ entities in which L 2− acts in an unsymmetrical mode with N 3 O donor set wrapped around marginal copper(II) and with the remained NO sets bound to the central copper ion. The marginal copper(II) ions are in distorted square pyramidal environment, whereas that of the central one is square planar. In 1 , the peripheral copper(II) ions (Cu1) are disposed linearly with a two-fold axis passing through the central Cu2 and with the Cu1⋯Cu2 and Cu2⋯Cu1′ distances of 6.755 A. The linear trinuclear units are bridged by a rare µ 3 -1,2,3 perchlorate ligand thus describing a 2D network. In [Cu 3 L 2 (H 2 O) 2 ](ClO 4 ) 2 ·3H 2 O, the Cu 3 L 2 2+ unit is capped by two water molecules. Here, due to the intramolecular hydrogen bonds, the metal ions are disposed in the corner of a triangle with the Cu1⋯Cu2, Cu1⋯Cu3 and Cu2⋯Cu3 distances of 5.976, 5.314 and 5.760 Ǻ, respectively. In [Cu 6 L 4 (N 3 ) 2 ](ClO 4 ) 2 , two Cu 3 L 2 2+ units are bridged by two azido groups thus forming a macrocycle of six copper(II) ions. In [Cu 2 L(CH 3 COO) 2 ], L 2− acts as a symmetrical binucleatig ligand through the two N 2 O sets disposed on each side of the piperazine ring and pointed away in opposite directions. The square pyramidal environment of copper is achieved by chelate acetato co-ligand.

Three coordination polymers, 1∞[Cu3L2(NO3)]NO3·2MeOH·2H2O (1), 1∞[Cu3L2(N3)]CH3COO (2) and 1∞[Cu3L2(H2O)](ClO4)2 (3), based on the Schiff base H2L (H2L = N,N’-bis[(2-hydroxybenzilideneamino)-propyl]-piperazine) have been synthesized and characterized. X-ray single-crystal analysis shows that compounds 1 and 2 are isostructural and crystallize in a non-centrosymmetric space group, P212121, while complex 3 crystallizes in a monoclinic system, space group P21/c. Compounds 1–3 consist of trinuclear complex entities, {Cu3L2}2+, connected via different bridges, nitrato (1), azido (2) and phenoxido (3), depending on the nature of the counterion. The cryomagnetic measurements reveal weak ferromagnetic interactions between the copper(II) ions bridged by the nitrato ligands in 1 (J = +1.026 cm−1, H = -JS1S2) and a weak antiferromagnetic coupling between the copper(II) ions connected by azido groups in 2 (J = -0.295 cm−1). The exchange interaction between the copper(II) ions connected by two phenoxido groups is antiferromagnetic, J = −12.780 cm−1.

A homoleptic ionic Cu(I) coordination complex that was based on 2,2′-biquinoline ligand functionalized with long alkyl chains (Cu(I)–C18) was used as a precursor to modify a carbon nanofiber paste electrode (Cu–C18/CNF). Randomized copper oxide microelectrode arrays dispersed within carbon nanofiber paste (CuOx/CNF) were obtained by electrochemical treatment of Cu–C18/CNF while using cyclic voltammetry (CV). The CuOx/CNF exhibited high electrocatalytic activity towards glucose oxidation at +0.6 V and +1.2 V vs. Ag/AgCl. Infrared Spectroscopy (FTIR) and scanning electron microscopy (SEM) characterized the electrodes composition. Cyclic voltammetry (CV), square wave-voltammetry (SWV), and multiple-pulsed amperometry (MPA) techniques provided optimized conditions for glucose oxidation and detection. A preconcentration step that involved 10 minutes accumulation at open circuit potential before SWV running led to the lowest limit of detection and the highest sensitivity for glucose detection (5419.77 µA·mM−1·cm−2 at + 1.1 V vs. Ag/AgCl) vs. Cu-based electrodes reported to date in literature.

The heterometallic complexes [Cu(VO)2(CSN2H4)3Cl(OH)4]·H2O, [Cu2(VO)2(CSN2H4)2(C2H3O2)2·(OH)4], and [Cu2(VO)3(CSN2H4)4(C2H3O2)4(OH)4] were prepared and characterized in terms of their molecular electrical conductivity, electronic and IR spectra, and thermal behavior. A polymeric structure is proposed in which a thiourea ligand is bonded via a sulfur atom to the tetracoordinated copper(I) and via amino groups to the oxovanadium(IV) ion. The polymeric nature of the complexes is due to bridging via the OH, thiourea, and/or acetate moieties between oxovanadium(IV) coordination centers.

New mixed-ligand complexes, [M2(BAMP)(bipy)2][MCl4]2, M=Co+2(1), Cu+2(2), [M2(TAMEN)(bipy)2][MCl4]2, M=Fe+2(3), Co2+(4), and [Fe2(TAMEN)(bipy)2][FeCl6]2 (5), where BAMP and TAMEN stand for the Mannich bases N,N′-bis(antipyryl-4-methylene)-piperazine and N,N′-tetra(antipyryl-4-methylene)-1,2-ethane-diamine, respectively, have been obtained and characterized by elemental analyses, conductometric and magnetic susceptibility measurements at room temperature, mass spectrometry, UV-Vis, infrared, and mass spectroscopy, and 1H NMR spectra for the ligands.

The synthesis of Schiff bases N,N′‐bis(4‐dodecyloxy‐benzylidene‐N‐propyl)‐piperazine (2) and N,N′‐bis‐[4‐(4′‐octyloxy‐benzoic)‐ester‐benzylidene‐N‐propyl]‐piperazine (6) in a multistep process is reported. The intermediates as well as the products were characterized by elemental analysis, melting point and IR, 1H and 13C‐NMR spectroscopy. The complex formation of these Schiff bases with copper(II) perchlorate resulted in disruption of the imino bond and yielded N,N′‐bis(3‐aminopropyl)piperazineperchloratocopper(II) perchlorate, Cu(L)(ClO4)2, where L stands for N,N′‐bis(3‐aminopropyl‐)piperazine. The nature of the complex is established by elemental analyses, IR and Raman spectroscopy and its structure by X‐ray diffraction measurements. The mesomorphic ordering of the ligands have been checked.

The heterometallic complex [Cu(VO)2(C10H8N2)2(C2O4)3·2H2O] has been prepared and characterised by electronic and IR spectra, molecular electrical conductivity and thermal behaviour. A polymeric structure is proposed with oxalate and 4,4′-dipyridine acting as bridging ligands and VO(IV) of C4v symmetry and Cu(II) in octahedral surrounding the oxalate anion V4h.

The new Schiff base N,N′-bis(4-decyloxysalicyliden-N-n-propyl)-piperazine (ZOPP) was designed and synthesized. Structures were confirmed by elemental analysis and IR, 1H-NMR spectroscopy. ZOPP can act as ligand through the two set of donor atoms (one set: two nitrogen atoms and one oxygen) situated on each side of the piperazine bridge. The nature of the complexes depends strongly on the metal to ligand molar ratio. Thus, starting from metal to ligand of 1 to 1 ratio, where M=Cu(II), Ni(II), binuclear complexes with a polymeric structure have been obtained, whereas at metal to ligand molar ratio of 2 to 1, discrete binuclear complexes were formed.

The thermal behaviour of the mixed-ligand complexes of cobalt(II) and copper(I) ions with antipyrine derivatives of 1,2-ethanediamine or piperazine (BAMP and TAMEN), with water and with 2-mercapto-benzothiazole (Hmbt) was investigated. The complexes contain 2-mercaptobenzothiazole (Hmbt, in the case of cobalt(II) ion) or dimercaptobenzothiazine (mbt–mbt, in the case of copper(I) ion) molecules as ligands and perchlorate (ClO4–) or thiocyanate (SCN – ) ion as counterion. By heating, water and ligands release the solid phase at lower temperature. At higher temperatures process of different organic reactions of ligands (e.g. polymerization, polycondensation) could be suggested to interpret the relative high final mass values.

The synthesis of the Mannich base N,N′-tetra(antipyryl-4-methyl)-1,2-ethanediamine (TAMEN) (1), its crystal structure as well as the synthesis and the crystal structure of the copper complex [Cu(TAMEN)](ClO4)2·H2O·DMF (2) are reported. C50H56N10O4·2C2H5OH (TAMEN·2EtOH) crystallizes with triclinic symmetry, space group , lattice parameters: a = 877.3(1), b = 1078.1(1), c = 1433.3(2) pm, α = 71.93(1), β = 82.16(1), γ = 84.54(1)° and Z = 1. The copper complex [Cu(TAMEN)](ClO4)2·H2O·DMF also crystallizes with triclinic symmetry, space group , lattice parameters: a = 1279.2(2), b = 1485.6(2), c = 1513.6(2) pm, α = 98.04(1), β = 101.24(1), γ = 94.66(1)° and Z = 2. The copper(II) atom is six-coordinate with an elongated pseudo-octahedral geometry due to a strong Jahn-Teller effect.

The syntheses and the crystal structures of the complexes Co2(BAMP)Cl4 (1) and [Cu(BAMP)(H2O)](ClO4)2(2) are reported. 1 crystallizes in the monoclinic space group C2/c with the unit cell dimensions a = 3129.7(4), b = 772.9(1), c = 1503.4(2) pm, β = 112.47(1)° and Z = 4. Cobalt(II) is surrounded in the fashion of a distorted tetrahedron built from the NO donor atoms of the BAMP ligand and two chloride anions. The copper compound 2 crystallizes in the monoclinic space group I2/a with unit cell dimensions of a = 2539.0(3), b = 1448.1(1), c = 1887.0(2) pm, β = 93.40(1)° and Z = 8. Copper(II) coordination can be described as a square-based pyramid with the N2O2 donor atoms of the BAMP molecule forming the basal plane completed by a water molecule in the apical position. Spectroscopic (IR and UV-Vis) and conductivity data of the new complex compounds are presented. Neue Kupfer(II)- und Cobalt(II)-Komplexe mit dem BAMP-Liganden (N,N′-Bis(antipyryl-4-methyl)-piperazin). Kristallstrukturen von Co2(BAMP)Cl4 und [Cu(BAMP)(H2O)](ClO4)2 Die Verbindungen Co2(BAMP)Cl4 (1) und [Cu(BAMP)(H2O)](ClO4)2 (2) wurden synthetisiert und durch Einkristallrontgenstrukturanalyse charakterisiert. Der Co-Komplex kristallisiert monoklin (C2/c, a = 3129.7(4), b = 772.9(1), c = 1503.4(2) pm, β = 112.47(1)° und Z = 4). Das Co2+-Ion ist verzerrt tetraedrisch von den NO-Atomen des BAMP-Liganden und den Chlorid-Ionen koordiniert. Die Cu-Verbindung 2 kristallisiert in der monoklinen Raumgruppe I2/a mit acht Formeleinheiten in der Elementarzelle (a = 2539.0(3), b = 1448.1(1), c = 1887.0(2) pm, β = 93.40(1)°). Die N2O2-Donor-Atome des BAMP-Liganden bilden gemeinsam mit einem H2O-Molekul einen quadratisch-pyramidablen Koordinationspolyeder um das Cu-Kation. An beiden Verbindungen wurden spektroskopische (IR und UV-Vis) und Leitfahigkeits-Messungen durchgefuhrt.

Two new Schiff base ligands 1 and 2 (where 1 = 4-(2-hydroxybenzilidenamino)-phenyl-4-(decyloxy)-2-(pent-4-enyloxy)benzoate, 2 = 4-(4-(decyloxy)-2-hydroxybenziliden amino)-phenyl-4-(decyloxy)-2-(pent-4-enyloxy)benzoate) and their copper (Cu)(II) complexes have been synthesised and characterised. The derivatives were fully characterised structurally, and their mesomorphic behaviour was investigated by polarised optical microscopyand differential scanning calorimetry. The structure of Cu(II) complex having 1 as ligand (3) was determined by X-ray diffraction. The Schiff base ligands exhibit enantiotropic nematic phases, the Cu(II) complex 4 shows monotropic nematic phase behaviour, while compound 3 does not show mesomorphism.

The new sulfide bridged-polynuclear complexes Cu2(VO)4- (C2O4)4S2L4ċnH2O, where for L=1, 10-phenanthroline, n=5 and for L=2, l0-bipyridine, n=7, have been synthesized and characterized by elemental and thermal analyses, electronic and IR spectroscopy. These data as well as magnetic moments and EPR spectra strongly support a structure in which four [VO(L)(C2O4)(H2O)] units act as ligands toward the two copper(II) centers through the oxalate anion. Each of the oxalate anions act as a tridentate ligand and the core of the complexes involve a copper-sulfide-copper moiety.

The reaction between copper(II) acetate with 2,2′-bipyridine and K3[Cr(C2O4)3] leads to the novel salt [Cu(bipy)2(CH3COO)][Cu(bipy)2(Cr(C2O4)3)]·∼10.5H2O, 1 (bipy=2,2′-bipyridine). The crystal structure of 1 consists of mononuclear cationic species [Cu(bipy)2(CH3COO)]+ and heterobinuclear anionic units, [Cu(bipy)2(Cr(C2O4)3)]−. The tris-oxalato-chromium entity behaves as a monodentate ligand toward the copper(II) ion within the complex anion. The distance between Cr(III) and Cu(II) across the bridging oxalato group is 5.056(2) A. The copper(II) ions exhibit a distorted trigonal bipyramidal surrounding in both cationic and anionic species. The π–π stacking interaction between bipy ligands of the neighboring [Cu(bipy)2(CH3COO)]+ mononuclear entities leads to chains of copper atoms running along the b axis. Magnetic susceptibility measurements of 1 in the temperature range of 1.9–290 K reveal a quasi-Curie law behavior, the magnetic coupling between Cr(III) and Cu(II) through the bridging oxalato group with the bidentate/monodentate coordination mode being negligible.

This paper describes a new case of the bis(antipyryl-methyl)-piperazine [BAMP] ligand being in the “boat”-conformation and acting as a tetradentate. But unlike in Co(BAMP)(NCS) 2 , which is the only complex with BAMP acting as tetradentate known so far, the coordinated copper(II) is connected via a iodo-bridge to a Cu I I 2 -moiety. The synthesis, elemental analysis, spectroscopic (far- and mid-FTIR, UV–Vis) and structural characterization (X-ray diffraction) as well as magnetochemical and conductivity data of this novel mixed valence binuclear complex Cu I Cu II (BAMP)I 3 are presented.

The synthesis and properties of new cobalt, nickel and copper complexes of general formula M2(TAMEN)Cl4 [M = Co, Ni, Cu; TAMEN = N,N,′-tetra(4-antipyrylmethyl)-1,2-diaminoethane; antipyryl- = 2,3-dimethyl-1-phenyl-3-pyrazoline-5-one] and the 1H-NMR spectrum of the ligand TAMEN are reported. TAMEN bridges the two metal centres via two groups of donor atoms, each being formed of the carbonylic oxygens and a 1,2-diaminoethane nitrogen atom.

The new heterometallic, mixed-valence compound [Cu2(bpy)4(C2O4)][(VO)2O(bpy)2(C2O4)2]2·10H2O has been synthesized, its crystal structure determined and its spectroscopic characterization accomplished by means of solid-state vibrational (far and mid FTIR) spectroscopy. The title compound crystallises in the triclinic system, space group P1¯ (No. 2) [a = 13.488(5) A, b = 14.160(6) A, c = 15.829(9) A, α = 87.22(2)°, β = 66.33(2)°, γ = 64.49(2)°, V = 2471(2) A3, Z = 1]. The compound consists of the cationic binuclear copper(II) complex [Cu2(bpy)4(C2O4)]2+, two anionic binuclear mixed valence vanadium(IV)−vanadium(V) complexes [(VO)2O(bpy)2(C2O4)2]−, and ten uncoordinated water molecules. The copper atom exhibits a Jahn−Teller-distorted octahedral coordination. The vanadium atoms adopt a strongly distorted octahedral coordination and form a characteristic O=V−O−V=O moiety with a significantly bent V−O−V link. The temperature dependence of the magnetic susceptibilities has been investigated in the temperature range 2−300 K and explained in terms of the ferromagnetic interaction between CuII ions giving J = 22.7 yJ (1.14 cm−1) and g = 2.014.